Recent developments in the cybersecurity landscape have created what I can only describe as a perfect storm for organizations maintaining ISO 27001 certification. A critical vulnerability in the Signaling System 7 (SS7) protocol – the backbone of global telecommunications – is now being marketed on underground forums for a mere $5,000, dramatically lowering the barrier to entry for sophisticated telecom-based attacks.

Why This Matters for ISO 27001 Certified Organizations

For those maintaining ISO 27001 certification, this development has significant implications across multiple control domains:

A.5 Information Security Policies

Organizations with documented security policies acknowledging SMS as a secure channel for authentication or sensitive communications must now revisit these policies. The assumption that SMS provides adequate security for sensitive functions is no longer valid in light of these easily accessible exploits.

A.9 Access Control

This vulnerability directly impacts Control A.9.4.1 (Information access restriction) and A.9.4.2 (Secure log-on procedures). If your access control framework relies on SMS-based verification for privileged access, your controls may no longer be effective against threats in the current environment.

A.14 System Acquisition, Development and Maintenance

Organizations must reassess their authentication mechanisms across all systems. The widespread availability of SS7 exploits means SMS-based authentication should be classified as “high risk” in your threat modeling processes.

Recommended Actions

As an ISO 27001 practitioner, I recommend the following immediate actions:

1. Conduct an emergency risk assessment of all systems using SMS-based authentication
2. Document this new threat in your Statement of Applicability
3. Implement compensating controls where SMS authentication cannot be immediately replaced
4. Accelerate transition to application-based authenticators or FIDO2-compliant hardware keys
5. Update security awareness training to address this new threat vector

Beyond SMS: Hardware Security Concerns

It’s worth noting that even hardware-based solutions aren’t immune to vulnerabilities. A research revealed that certain YubiKey models (prior to firmware 5.7) are vulnerable to sophisticated cloning attacks if an attacker gains temporary physical access.

However, despite these concerns, FIDO2-compliant hardware security keys remain significantly more secure than SMS-based authentication. The YubiKey vulnerability requires sophisticated equipment and expertise, making it primarily a concern for high-value targets facing advanced persistent threats.

Advice

The telecommunications infrastructure developed in the 1970s was never designed with today’s threat landscape in mind. As ISO 27001 practitioners, we must continuously adapt our control frameworks to address evolving threats. This development represents a significant shift in the risk profile of SMS-based authentication methods.

For organizations undergoing ISO 27001 certification or surveillance audits in the coming months, be prepared for increased scrutiny of authentication methods by certification bodies. Auditors are likely to raise findings against organizations still relying heavily on SMS-based authentication without appropriate compensating controls or documented transition plans.

Have you assessed the impact of these SS7 vulnerabilities on your information security management system?

Always consult your certification body for specific compliance advice.